SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc9d41586ccb18add9b41b8e5a6af48f55ad22470ffeb2b91c369d6b7eb09516' 
  AND token = 'p4xqdn+vgBMDPDE2FzLXUOo85SbiV4J3mGSbhmKnrOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}