SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3a8a5feae5b50e9ac8bdfb8f597da0f9ff0f028367e26b2262744ca26394dce' 
  AND token = 'yJvSCoZpIg/ueeZ6uYvVxwQfhNDl2vPW0m/o08P7Rws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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