SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3e28bb5175842c19990b8e9207e32ac6ad46265dff30432570b51a3d4afeee9' 
  AND token = 'AeHTqEIuHKIsnCqkQEApM8ImZn3iYO0TdFNslocLujQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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