SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cb8ad3970833ef7d1fe18582095e5571918b6e290c6cf5b45bb1c0aa4023887' 
  AND token = 'PZsUqY3MxR1nM4rhOvdYLnzXTfkxevQx8BwjVmvOxuA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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