SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf988098a70507ea3d077650f1dd0dc681e2aa69b6033c0aa4aa071294a9e476' 
  AND token = 'YmAuxVyDEPvwWRyIBJpfdx/i8/AuwwUoqyXx2bc2OTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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