SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b6c569a887584fcd2b756f4198c32a2a7e6418ee131734bf703b919694c76b9' 
  AND token = 'KKLK9C1bwU7q6lmBuraXyfXU3ZUDSk18SYhJsWXGHzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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