SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc526c46d452f09a46c03f821c8048cb424f336c0556e51043c6f4812b0cad9f' 
  AND token = 'KYJxqhH8Jo4Qo4JdOc5RZJvzwmXX4WehgPxsorJkNYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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