SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73795849bfd25d47af90b964ab55461c7802c84d49362043f0bd718bd401ba35' 
  AND token = 'n9ivpWC1RB5L6jUrSAsEuNml2bks9jOhICUGdY+nXYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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