SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b58d463b9fad729890f673110cdac25aefd6f3b50d1d3692bff5de03e88f7e7' 
  AND token = 'QW/axBweqKJVgQNHmdYQ6yO6GFmYmb8TzjGZFMepRk0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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