SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab6a1f50d01369105f1611c3efb55bd412e770e6d1c324af7632ff9bd1c01fab' 
  AND token = 'iayP5B5uEGfXi7kiNBObRiCpTKazjvhhCf6R13a4pq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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