SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11b9b8c40e3a44b2224da839b320ae1ad5449328ed9a398b0eaf4694fa344f50' 
  AND token = 'rRPzfEYPJSWFHqyqmDV92oC1fAgovN4PXqHGS9aF5i8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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