SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fef9cdb9d069462899946db55e066ff1762672d6ab2fe4b413f86349a78c3293' 
  AND token = '1+lIe9rhHlQZnMGsMOPUvu6+/wcejQAFLGNLh5jylUs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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