SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98e0eb480ee9e677b72c929fddac9ec158d1927493d11f1a8fe2686a0bf1fbce' 
  AND token = 'tStgJr6/lfuLYoSfANQ9VDf46KvnjxlwCULMYUDGzPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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