SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f0a13ab34347d9428032ff49556e71fe86dd87914d98fbb475610e66df1a6f9' 
  AND token = 'X1PxYoG+JsywxIz/xzRAlnQvJSkSfJhSASrw9Mxkj3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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