SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72b17fba0a0213533c4e6ac213e842371f67a7b7e98f70eabffa761d91b791e4' 
  AND token = 'MkSdIMx+AQPTEbBVrr+YLV3yXR6/RAY8GLPo2sRoN4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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