SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a14a0f1c4c0562e539cea3300828cab27c071560f9f1f3e5e317f2f2fd0e8e3c' 
  AND token = 's4M1mPMORLA6vWVDJAiVgqiCKGBOK8ZoEVhMEUyizzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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