SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcab823f6595bdd1029769a3240d4b38b1480fdbd9fdcf392379bfe788a4b20a' 
  AND token = '2dKZMzcPjFwDNQ/KcGqWoRS3XCM+D9tIxBZFJiWs1QY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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