SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ad5a395a7667188dda7f5ea274d40021d5e0e4745ae7196edec41cff4782758' 
  AND token = 'Tvdds+X4x4TYTCIVzsnG8zXB1WOoPOULv7gEyTZ2BcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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