SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49981d95991dcb84e523ae5cdb084fbc95ae0d46d6f35a0f4bbd3af76316ea40' 
  AND token = 'zGj2c9tIEbeTLYI9SYvXTPxVQpecjrFCHydK7uzUXg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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