SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '173aa70275019d501989d6b901c8f92e2859c8ae532ec192220f953d6c750249' 
  AND token = 'r0afF5adE4W2aMuI400oOIEtVduIjCI3nTZNZHxvy74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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