SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '07539f98d8e3008a9957facbc259e29405be53d8814ea1dfb254adb7be4f5dc4' 
  AND token = '1d7upRdQkHnJznFIN6yRIwTlh+i0Hq8PmkMwrxmsf10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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