SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25a431f40357273880859e1653f146f7a53e8dee3bb54f885d852e7eb450f9dd' 
  AND token = 'b40LvTRNOh1MsbWPpZY46qgTHlMwolweIbwW/6HBhjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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