SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e403f60b244d74733aad9731d2c6e8791f3a59a092f165335fe4da52ea5b894e' 
  AND token = 'elSg5ftQwK2+yqHtiBfb3peGOlAeDFpj2YUgfDq1fEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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