SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71235b105341c42711bb66c6def0b7c278414d71177242decff41616a3aa7fed' 
  AND token = 'Z8pLCF8aF6DO/JnWiBqkTMWhHPYZCDrXNN90BbpYUMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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