SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8edcc255b51f8576ddd0af7b505f3bfdc8d0ec7349a2e1db9d5bd26ad2ffe19' 
  AND token = 'h55jwBKi0jEAVCKndKwLJ+sb/De2yeNg8fAjEKpOWxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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