SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f4bc11c83a4816931627a50298082d750ad5768c6e2c06988d786fb59ec60e8' 
  AND token = 'wyVtd4ZP0lOobfsnWfHnOly7yFwwlhB6j+ZNdoIFkRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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