SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6273cb7593867651e72a4efdef82c84abeb3d55aac48abc5f4a8dc2c9ac101dc' 
  AND token = 'Tm+xXyZ4rCjRn/LDbbKp7ghrhoq8XB3EFI4wtIkCLfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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