SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b748f8fee962c560363c605a75e5f3fcc53e4101797c86290395af94dbac22d' 
  AND token = 'Ya4SUpKJCxHwDbVAyJ2QIrmmno+Nvj+CP5EFrJSpin0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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