SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e3e6b4dd682fbcf6eb5e9385b9f264f09cb6a3d937a929524461ebdee1dd54a' 
  AND token = 'HlS++c61wRhQC9S1W8azgrOwrrYFdQa7N6A0BGZj4Fw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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