SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6449eb4e977ac53ca8ff347e79e11756927bbc03c4a366c85b0c405400907e64' 
  AND token = 'pRhYh773z/bq0PAbqNa9JrYdYt/nH02li+exSK6NNgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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