SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62b93bda1bc7ede2b93a11e6f0cbb189e5727906558d243f25cc9a9da3bb1a07' 
  AND token = 'KsBTEPglUpY6qUTTCLeTEBM/e7U+4IELKWvy40DWrTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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