SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc3b77d5348a9f0cf52b054e739efcb7beaf8b94fc5f5b3ec6ba08ba242216f4' 
  AND token = 'Br0YMwHMoBKq0+RbIO/lVM2/YfKV7F3Vw6q5ogBXngg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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