SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15dba2ae29317be8f1a7aa1df6bade6ec7bf50a4a9a58149998750c57a70177d' 
  AND token = 'f0sy3+xYH6AcgXjsOQXc+pyNrPsjbDqaWU22KiG4VjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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