SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de784a019b18fcdecf1a2b7afe1531b22a817cd84d6c43a56699064c26afbf59' 
  AND token = 'zon/3q9wOjDDanNBNHfVk/xn+0+wVgKKiL/zjd4NzO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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