SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4174a40420ad46445dd83092befd4a0237b6cf71c214d9d048c71c7744ae573' 
  AND token = 'V0U0w+2/zujHy8S9yBcRc3P6cFut/hA5JQ76Hg9b53c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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