SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d344d0f1cae0107564b79ef6795bf2941922399e8310cdef1348d356bffbaf8' 
  AND token = 'djEFoEfEYERoMuoSFOOFzVa3KFbI7SvsKfOcscPtDl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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