SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c661d66f36e710ec7b0355a7d8873423954abd2d1c4f3cff3436d49db102490' 
  AND token = 'Ld6uglsAEK5O+//kqOlYuQ9Zg+lxpvymMTQDGzejx2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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