SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca318dc6ea1e51bed6ddddf61bcb88fa9fbaa091602e303976976fefcbb7827b' 
  AND token = 'oOpSNpEvLQHHTBNqpPKIOM7Kpsqq8QGURsTGBvKc7lI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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