SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc7e45f9a4d8962828ede5f32552d687ed7dd76e168ac43276a794ed7d365f8e' 
  AND token = 'XCYoJFM7AjMD9FlHjuZx4BBWBJ6x5BwFMLD4tNqQyHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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