SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '313a2e65ee7101f76d5adae36d1fc5467fe05ddad66870cf5f57e02a2c802ee9' 
  AND token = '1Uznkss7dRUzDPP7LZnxCPoj2LGuCPWxYaGHRquMDZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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