SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a0155c2917992885ea317868615916682e1e53f9d8cc9bd6960d7da874314bd' 
  AND token = 'IhLtRLxGLmZyt5TNLWFamP7a0+FtntMrRX9F3tTbi7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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