SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '92703f6d294e42746799c6b5edde604097e793388ce3501ff0b358b11e1a644f' 
  AND token = 'KyUiwVE5hznc23DxAjO1ePLh9IHqLHqwoSK8M9mOfo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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