SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4128b2a0a644a656e9a8bddcccd411ea16a516e76614f4d719b20addf5318004' 
  AND token = 'csEU2gDkduvmqYWUfn+NXjUa7PywVmENdFHTGAb131U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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