SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4f48d97265534a908964cc8408c5b22da7c3906e2afae2888bbc62c95c115848' 
  AND token = 'QsIsztqV7UcLmwocq3trj07zwAqMilcva9Ei2BRdkqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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