SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78cb7e1b4decb0baa2eaa02b297c306b6d6fab47e8ca80937093dc5b37834fdf' 
  AND token = 'OKSy2CEdQZw274ywTOPR59bAnjWFJM96m5HCpltFC5Y=' 
  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"
    }
  }
}