SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c8015c86474237b3dc3a536e749d42053fb4ca46aa989984ddf917e932d765d' 
  AND token = 'PAldI9+scBRByfivthyMg8LLc3TSsFVq7HfLQjGsQ5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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