SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3b3b8f1daea73c1df843868ab18278884ca6abd39f1bf17d55ccd0a804b74ed' 
  AND token = 'qLDJPgq/Ilz52o/V27n+0d/CCUdjDLKTDSICLWLR8bM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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