SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2ffa179d721e586350c91724c6f8fd3f2b317698cb57bea218baaa8622ec5dd' 
  AND token = 'BQxzhFdUTcoaACwvVidADiWKs8mR1uZRgOgMdPf/9pw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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