SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba8314ee2decd7b2081a16a134da5aa39b748bf6e7f266f8b77fa4cc45ba6a2c' 
  AND token = 'IR8Gx/YBIp7bSGFjszVDWZ68ZrspPGqu7XcgoOcDcVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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