SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9be25993b8ca233c417ce25a692d0c2fbd083b8028100ee5093bfa0723bdb50' 
  AND token = 'ulRPP/A96RxSK1uXkERjH15ToCHI1wgRs3ODOK3FOtg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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