SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c44d206da0f976c57b210f9c93530fda308cea17b8052df113816f4e138b245' 
  AND token = 'FH4++Pygbxxf7idgZhvQzdY7aJffjjgNRcu/awnNNs4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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