SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27f8811767415b70837dd53909a12c581c997e3177fa67b485320d1a5c2023cc' 
  AND token = '+14JDff+ZoB9LqHu98KApwpqdhMB3YJ+P3gtdHx1EhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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