SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a44fdfb48296a35ff5fa9c1d57c8a5781443df6186f089e000e44a477755d568' 
  AND token = 'IfeiVYO9RXdUTUqkBuN1BKOKU/gXTS8KWoKm+M68gQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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