SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49e71b4899765707cda197200408530dae49b1ded0340e5efe8831b5dad8e4d6' 
  AND token = 'kFVBMUWrTGiIvprlBsnA7FY75Ha5F216yYNNBgmM4PI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}