SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d7234bb4769f787fde615413ace2d216482df87b3b9aea489f46a00f0b19927' 
  AND token = 'WB9be1UvimEyt2TZ0TiJkZygH9kZLyJ9nnbYezzetOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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