SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e505512979d40628cf219328384dfb1716d48e17a64779eefbebad03feff57f' 
  AND token = '/xpCyPWKBH9ddApB80oNllpYUqnIndIzR40BOq6qcx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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