SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9917f14111cb79448d70967c482b42147b11226a348f9f939279ec01aae50b1a' 
  AND token = 'gvg6n3tx2MvkeCMScQGVxb0wRf1adp1pQqutyPMYn3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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