SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '944b678d453b8d9998e93358f9dbfc3677dfa872c13004b75f868f32af2b0d29' 
  AND token = '5REJArC6rU/yHDFJqdgeZ+Vwq5bzfmdA2EG7I7HswLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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