SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50fedd5f566725c091a35bf62eafb45fbc7993a7314d63b5e74c9f488337485c' 
  AND token = 'bMFijLpF4oHUDXogGgt44oFnvFSIjj2hqkNqYdndR64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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