SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '1e57e675d165809e92ceffdac09103d56ae1499fd4806f4297da93fc5a7040bf' 
  AND token = '26svuT2KpPAVhXHMC5DC7O6lKrwWC7HVJywwQyDwdxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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