SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d38b1108531d2c4f58510a5a555f9a00a873a0b277f4b26dcfd8159db5c58b1' 
  AND token = 'J5VnlRWbzTwyjJ5zoeeF9pmWVrZXnGPHNMqaQxTDObQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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