SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38c148af08c6c4a73aa726cedc560e0df760841bd5c6722ef3685495e10f54ea' 
  AND token = '8fyb4fXlREKS53uYbD0dcDBlr5386e6KUlAIxKcgZqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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