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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecb5cea2839e514ddeaa6ea04f2c56e11128c29a0f4a49ac5a3f7f7dc2be15d3' 
  AND token = 'eVyj95wde/nm+RFAraJO3VBZYVuvhOwqYYwSnWsy5JY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}