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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a54d2709ed96cb2875fee95c95fca01b29a1fd2b4292e731707324e3aea85a7e' 
  AND token = 'Gx7fGkbK7r6Nrfd7H0ypOhEUwAmdo/SvYdJuhw+Aj6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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