SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aeabadcd56d5811ab535abc6b41f30fb63995833f0da388579da20fded45767c' 
  AND token = 'KCc4rzepdrR57DQOrKESFOr0BjL7cP7VpvINo9z0Iw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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