SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c14da1e08965aba048276b50fc0c709fca79bcd1b3cb0a4863ac08a63b84e04' 
  AND token = 'MgN+A23yeSVsWxXOKKFDRMEhHl21GR0PN5+G+myFpRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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