SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '515045fd56e2a9fc8910582963d74fb4269c5c56dee25bdb3c28790dfff86ee4' 
  AND token = 'TcQBK+NJeyLaczXfhL1wMZ7IaWe1MHPxcXiljEaQ15g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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