SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de515a488c0aa9668e1429feb42f9b13753ddd63da4e507147bcb438a6fe4a3b' 
  AND token = 'cN57aiURtRX/I0dBkrwsI/A8o/hLLlp0WJnkiz9Cppg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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