SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c19175035886583a92108c405833f6dad7d5753720f108e0253af38d9925155c' 
  AND token = 'DeLL4WZPLHoP5YPktqcto4OuYjrTCKMChZVWj3EJQCo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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