SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '185370e215097e57134d4985724f100515567b67cf15d93a986cb615df7e3ab3' 
  AND token = 'WALBeaGFwVPC4u7zbO6TKmUM7XwzYaXpKehU1gK1ggw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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