SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d9e1ead962ffd56c65a4d97fda98568505662901c84381540376d8301bb0734' 
  AND token = 'Q4k1ldPyknxt7FRuxXEWx/e6YB8V/PhAdqUsVfduExw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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