SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e7b87a3e85d8a23931e2bd441890e26921921287785756bcd54bfd62bb18a4a' 
  AND token = 'EOWkPe0S31qmJgPFaNU1dvYg2ZT71ucrSpnJf5DivYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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