SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ff2d90e860e17c4c77c73e004ff432f422e082f7c24507c00164b74a934c90f' 
  AND token = '5x890caI0SzaPSljqq35OZ/V+RWlxmryBbtQphUxGLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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