SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c336a3abd61f135f627445d5cb817889bfcd38c517a2e6482650539418d41bfa' 
  AND token = 'VEVuKHnC7qgCVIDAW6TnwPGN5f8JnbwXAseyhQwRZtU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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