SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12dd563d4f47ed48ee8b8766e8c57ab9a06f606d49c207925e913f6cb5b3307b' 
  AND token = 'm/vJeSzcKN+DGOfwIy6CjoWqtzubCEuG7658HJlD70w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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