SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9459c82df4b6b6f69b1be76db8985ee1945d770a5c3e0206dbf78f99ccc9f26' 
  AND token = '2qMr+zeuiYnMmr5TjAQFOAi35nFm3LJ+3D9hnDWTbmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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