SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a458a82f856ecddf663c4b24190c5d935674cc7dda8f58727817527e67c7df0b' 
  AND token = 'MEO4Ggh4+UbpchJV6hGnCAGhHaz/ptOYJOlwuYJ87H4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}