SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c0ee8fe7f61f083039ee874c57cd80009f8c1d08ab55fc8ca4b1c50eb151b34' 
  AND token = 'C+1jxBgnvnH3dTVrPe/UlkrzTxvZMdY2bmsDBxaSTVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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