SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8eb1075deca96877d16de8ffb796172b31be8e1c2429e697ae315d0bd3972ee3' 
  AND token = '3Hb6cQvMx4+FLugzQCXZZzFZQMfTDyNfjkPzURrgb18=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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