SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ced0a88d7f65460352f56c2003de0a2542cea2f1f79847dd1e2b60821076a4cc' 
  AND token = 'ycvU91qC2G6KZ8fQeDJYdYd4PIRUc7+AXJ/JTFvBSnU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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