SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9dbfc0227a08ce4b1b84cd898b15612209ec9ec6628634989a3a1f378b53ab1' 
  AND token = 'O3CkOqmWJ9+hsM2GMBmcd306+SrirWJ0aGOxhJRk9xg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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