SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '435a86cf158b58c543d915c4de13cdba303238467d7cbee4c5aa99dda1aec319' 
  AND token = 'zYSR6/1dyQsOIGclqQjI+pd9z0eF1QsDskx5SMVlYeU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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