SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a55a67e39eefb116ca1123871fc9867e9245fa1334aeae183a66255cced030f' 
  AND token = 'pZCttW+dgvQrqn67S/+6w1BJYXpWYcMQSjnCu2iMci8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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