SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5b31213ec948f92f6f8eb5187354ad12e0920943ccf5e115897a46040ee96ed' 
  AND token = '7CUFJv4vffgFLsnOFwn9oZCDDOW+VxS+X2ZbYTpxRsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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