SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d395ce3d7b93948351248b0f9051763feb4a1f58d94cb45c8d3ac6bbcfd7847' 
  AND token = 'KLdsFFpv7vuD58+Ws/VYyLOfVFeEgImiJgqDyjg4IOs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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