SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5fe85c17b6ebd0d921742ff8fe20c0c4ed6be8c1ae9e8a7a267a70588e3aa70' 
  AND token = '98+cqvba8lzsdQUscjtctpDEXzSWxZbNXU9dJDN4XRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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