SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7ee15ce799a351b99b7fea0f83f8a526a8cb00bb03517585a4f920670d4a9e6' 
  AND token = 'Y20J0kYK6fTBUkS3mB374dhPUkp6q7L4dzWoxeg26RE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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