SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa5a74923c107833e06711ae51f468afe68ad3374584d980c3df643dc51cf7b6' 
  AND token = 'O5spszbaM17sI/2VhgjLMKN84LBzl9yFidRZPgMiwLA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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