SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f09fd07c76f3724b5a4c4deffb3962a265fbc888514d5ac6e6e045415a79d613' 
  AND token = 'sQU4KByXTkwpuRNRny5YH5XgMbzEVZxD3h3+c2tKzvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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