SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99b2eb56ab713e5ba5ac65ce3ec51b3f9a06335426383d844ce66b7c4f5a66d1' 
  AND token = '4WPy8RczYYTI0Sf+PolKl8DBKhc8A4F68V+Ag3nSVJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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