SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b537d683c88a812dcd2f25bce19df7870aeb5fae2bcbfea59f4c2bb614db0f6' 
  AND token = 'QB6kQRJpeOKiGtH+JHZiIjKv29kWVQGu4VwttxX8KZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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