SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b73dd786759e18eba239b666d6299cb953f2cca98340de158bced5e121de6dcc' 
  AND token = 'M/bTvB4yozD20nPOBZvIQrl7D8m5OqPy66TVfJhW1Pk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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