SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bb1e8d6f1caf1cd476ccd0c9a38379a0331e01ea00ad379ecac8d917085a392' 
  AND token = 'jedcluT7XwUvHhZOngi5rBB2/nlJKVXiOehGt0qn5H0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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