SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b10d8945d6c87cd05f2e2105e29f6d610a3cb8a6832b6aaea3a21d313c620b4' 
  AND token = '2qTY1r2LjnaSGik+f1xiwKspj86nsYrtzHrzXJE3e94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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