SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df101b99e24bb7deadb3e71f6c9cfafab347c9f8b9ea1aa7b23b8d2d21f889e7' 
  AND token = 'uaHLJ0FKLIAxCXxbVtoKmnAEP2gDNUT2ffegQr+tADE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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