SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e631646ce4a03264bc23240ffc1e2556750ad050e473afc9ef90501e46e88920' 
  AND token = 'a7IyeunWt8LQVJF7FmcXpzxLKge/dqWC+t6iQRrKBk0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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