SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cdfd76e51da8894e8e8ad81f1e65fd1c49a4fc0dd61a9cc9d99c6643a066868' 
  AND token = '1Y9Bnn0gJvAbeBRLFKgYIg1DAgBBD8bGc2B6Pnp4OqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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