SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61ca0a2037af7608c0f49dbcbb09460f5583b5594f212d04cbf8d5f5ca0c3e47' 
  AND token = '4C+uCJPndBt44ZUTCGZy/U82ZfBbqeOG5YjHJwC4khk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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