SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd816d2aa64902b6713b58b91125f5b1cfe2d34d11b6386224a983d8a6c134240' 
  AND token = '08hbOGqqxgImuB5Eu60wby//lXUzgQJyeVpxDK8w878=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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