SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3036eb04c80f4bbfe0da4e53a91122969adf94ecdf8888df4fecfcb1f957521' 
  AND token = 'JvTDTFchzAoqMfumycv2FNPuMZOi2IXEY4Ps7m9//vU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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