SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b25a7a4c4982409ff3362ea48b07f1f43b3e68618a752fcdbb99633896bd235c' 
  AND token = '1ExwYVTQNbs3Q/A5yQmHvVpHUfmjPAGYuN48jwJ7m18=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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