SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd8b3b371f8a49e1ffdd586323f0c03c506be6599f135d82ce697b67e0cb2d90' 
  AND token = 'b6h0CZxDvqAw18QLs4PmXx1EgygewWdwKa5fYkApKkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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