SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ff469ab4345ffa339a901422703c15b5123473728d3c66ec9f0cb74d8fc0b7c' 
  AND token = '67TyxrZkP/62OhdVMvSkPShDnlKtOAQp0dNvDFFFBFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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