SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df1f6f06677693d5446e4c643a4db3bff0ec93c496de316d6a4f7b98a8cfd37c' 
  AND token = 'owrFswfNPgtZGfmKzeZFJrFuFZJMerZm4fyUvgSuTxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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