SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aea59ed7f86f7789ed95c7e5461a26b4cd5a24706a5d1549314927346742236c' 
  AND token = 'MmSWgHzWrwJxHvagswqLOBYocfJr3R3cDADfCI0jXkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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