SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c92bbadf91f10501dd16c7de55ef1fb071fefb307b1047cc3682c8ad4c5717e5' 
  AND token = 'lyernBeSYEmLDVZ5a5YpVgTrrMa/WKlrtS69C3vy/a0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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