SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6207bd261fb299bb48c117f98dc2cb8a0503fba7385d79f9b78450e8a86cac63' 
  AND token = 'o94bXhAXTVBlah39E4o66osmFw0ouRkNY9kJfWSdqIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}