SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ab151d92a910904d15466503ef628754a2636d1202ad14097494ffee76f65d5' 
  AND token = 'Kml3JAWlFfeEeItEkeYZV0qybyJfin4bF3XD4XhjObE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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