SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '482c3c4628b31d6ebb150668c5e29cef0c2084dca1205382e6f5294d27b18152' 
  AND token = 'Js79SCB/TRk3eVBYN5ytVtwJzfq1eUZjaMxdbMg/leI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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