SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c087cd0045bd07d0e458385ced05eaad26a9309d12a092884f92f1bf65e2e6f' 
  AND token = 'BZzpK+dNmMUPbECLpbfDc1yIMFbe0dsvDecam16yWt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}