SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2dfc461552d59685095c222ded5257c04ccdb321ffec102119c8715c31560d5f' 
  AND token = 'dzibAV1NqdMK8G1DulkUpkIVgwP6PdPuR3hhaVsLgQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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