SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '068dfb1238d4435072defa293653afe2279ff2d451ad108e3bf7b678927c5074' 
  AND token = 'FVRLCIp+q5M3OnGtq/AyRk1LxCNVar9x65I4cNZHoAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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