SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '431c6d3659bf44ccf8709c0914dc62a68813fbbc3b94cea28a11fe541a218179' 
  AND token = 'xZT49NNMfEzswSBLLOnlOjACZBGAX+BKjKhp1S8yKPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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