SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6efd3aed265082fcfb4efd118ceccd3d35cc9305c9752ccf3f79a47abc79890d' 
  AND token = 'njRkT0vvVrMBLtU0wbc16YbWIsGV+GPxS7fuOSmU3DE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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