SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4eda28d24302e7116a5577c2b5c3dd817dfb9bb0ac49cf7ee057f26d256963fa' 
  AND token = 'R7/HFe+qHIFCVpuqvxDJ5Uf50PDTSYv0Jarbo+HeAOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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