SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2a030fb41d155757b6ae92a446b23712fb2ee38428acfa8856ee140f2c48096' 
  AND token = '35H+Bqv6o6zUvvcLFyP1Nz491FM//LGPcAg3wnZOmXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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