SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea4a353a4d6b84bcff2d32f62f424b91066df3bbce9b43f1357a7d6fd9668faf' 
  AND token = 'NYqNVMAlHz4C3jp6cFkueGOvEo+bWcqxBrHhvtVfwK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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