SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a264c937bfd8d8a9e870c63da74092cd0015cd97d8a7a911faaac596f0662ed5' 
  AND token = '8TzgWDs+VWoIXT9+tub44TVUP647BBUCiO4BbQjNJl8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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