SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96e57585e77a9705887f42b057b91edf8d7459905869bed7b5380d1a8607daa2' 
  AND token = 'BaNzR1kbjsSKRMYE9zbPVXhqJiCcxlpQ7rcr4G06EhI=' 
  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"
    }
  }
}