SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3449d5069da6c2ad739615c71ebb3ec2bd58a1cbd5315aff93337a8d8ea35a7' 
  AND token = 'XrEnseXAAT+UPmyxV5agnpKDhbL/Ol+iKydz0YdhZRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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