SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e4d68d9dcbe3f3e024aa09c2e50f53ef8b9345a86bfd120d42d6ba2f37341d4' 
  AND token = 'NvMBiVPKCJN9M1H74UdJ6Ke+8mD15oiVWw1fWf8H310=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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