SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71faff5a8db91dbeb7c36aa9bdb4ec6803778a3b040f801848ccba7dc1573c7d' 
  AND token = 'jzZ3JxQEJ/d8qDlkWwljbiCC1h13e12/+m2SmZtQWg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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