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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8f18e3aa56093c90539d061b9aae5a10a8df65b6387876b5e45c417aa29110c' 
  AND token = '/dRBQexhvnSqXDFRYt8ygD3IyFk1P8sa11r/NYr96cI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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