SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3efbcd2b7cadabf13122aaf47ed9a9e3037fe303021df6f750e00a40ca2cf927' 
  AND token = 'lYCb4GtHINHjS/EwsQAVLTMKj8E73tY6xPvQxq3Uiik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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