SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ea8517827175fa407b47b943b8df87f372aef1c36c2d3091eff7b39da7736fc' 
  AND token = 'qluazVeByAiPcbxc83w1EbmjbHM9bO7KIMUhEFN4+EU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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