SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c1830b49ba8b448597899a05f56c5cd7e63670ad659152189c31b15e0993e33' 
  AND token = 'nYTnjYgzPWbb5HeOkdI98fB+fAuQXITNRDlwlmj58B8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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