SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7be26340a1d2f4cd406fabe8096526ac43ca44cb993a4b23b480dcbacc8102d' 
  AND token = 'G/PJKj7hmK6tK8jTPrBufZaWfSge9qwzYOl+opxYzUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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