SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e871f6ab4b014857bbd86afc91e84d71ba34193a3c9a4355d13a7bfb423723ae' 
  AND token = '54aed7h+4yKYacXHzVmYd2WeiSXwPF/fxdBxpAZ+Mjg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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