SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11f72c20f44d20c31913ae273d85749d4113296a795fb50b6769e6a07bbe05f3' 
  AND token = 'P3FsFNqUwp6SUznHfC4AZJ5SCcpuLjlNyhJzCZqUd04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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