SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4199e21a747d4e6d90590bc4343cf98a7cf79f76e30809208ff2cd4ef8546b5d' 
  AND token = '/sBnXzantZrQccrigaJk7xYTFhDKLu46WZQCT55zH1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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