SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83455ff3228b83899eccb2fa125bb2490ad91106fde9bdd3fd635bd458476938' 
  AND token = 'oGfo4461vSr1ZCGDtcqurZusQrpgR1ld6zddpKJim58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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