SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30cb831c2298b0aa58f5c68b1527e48dca15173524fde3acc04df6d78fa04f37' 
  AND token = 'WjTDwwmVUyDLY+lo6bfKga9Sn7Wx9lIPi0Q/+KlgWOs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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