SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '734fd8f7215b03ad3f1bc84ed3896a897afda3113b911cfb9bf9467b994d2975' 
  AND token = 's9uJSn+yk7JDZrcO4qtolUFJrYiT4YNMSBRIiASSfas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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