SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5170a95feb0a31fedd236f9b16ba96f00fe0f802c7b596c0ee918daaa9579059' 
  AND token = '0L6cRZOY6zCuhUUch3BfjIhvrGemZhDo/f9ybT3mCBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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