SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de4eaafd85e107adffed67ee9442c020ad49b942a4137a207edb1f157a73c32a' 
  AND token = 'Rvm7m3pYIsGDJwi7pXcaBqMcKv1vpvJpn2hpZiDfLgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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