SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5891b8d6e33026f1787ae58978448b177d1aaa31ccf40a753d795d67feda7632' 
  AND token = 'PAeJKTHjs0jsS49DYrEHk0Hzhp22y19jpax2sDsMRkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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