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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c91772a2fa7bf1dcb796aaf6b11ae2176e6ab79963a5d784ebf12c61e6f4578a' 
  AND token = 'nzwQD7FeHlwHEgXcm9G3jRj7naPaF+sgmG8vmAcNrg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}